Washington: Older people can't lie as convincingly as younger people, are worse at detecting when others are lying, and the latter is linked to age-related decline in emotion recognition, says a new study.

Researchers at Otago University have based their findings on a comparison of young and older adults' skills at deception as judged by listeners within and outside their age group, the 'Psychology and Ageing' journal reported.

In fact, the study involved 60 participants being shown video clips of 20 people expressing their actual or false views on topical issues such as factory farming and stem cell use in humans.

Ten of the speakers were aged 30 or under and 10 were 60 or over. Two clips of each speaker were shown; one in which they were lying, and the other being truthful.

The 60 listeners, who consisted of two equal-sized groups with average ages of 21 and 71, were asked to determine if the person in each clip was being truthful or lying. They underwent tests requiring judgements of emotional expression and age in faces.

According to lead researcher Prof Jamin Halberstadt, the results of the lie detection test showed that both young and older listeners found it easier to differentiate truths and lies when the speaker was older compared to a young adult.

"It could be that older people are less convincing liars because the kinds of cognitive abilities required for successful deceit are also those that tend to deteriorate with age," he said.

Lying places demands on memory and planning ability and on social understanding, say the researchers.

"In our study, we also found that older participants in the lie detection test were not as good as their younger counterparts at differentiating between lies and truths," Prof Halberstadt said.

Further analysis showed that older people's scores in the emotion recognition test strongly predicted how well they would do in the lie detection task.

"As with our recent findings on older people's worse abilities in detecting social gaffes, and also older men's tendency to talk for too long and go off topic when talking, age-related decline in emotion perception was again linked to poorer performance in the phenomenon being studied," he said.

(Agencies)